Fractionating tower and scrubber



Nov. 3, 1931. J, F-f 1,829,949

' FRACTIONATING TOWER AND SCRUBBER Filed Aug. 16, 1928 2 SheetsSheet l W&

I IN VEN TOR.

ATTORNEYI NOV. 3, 931. J, vANDEGRlFT 1,829,949

FRACTIONATING TOWER AND SCRUBBER Filed Aug. 16,.i92s 2 Shets-Sheet 2 I NV EN TOR. (fa/7265 Var/17:32:17?

ATTORNEYS.

Patented Nov. 3, 1931 i v UNITED STATES PATENT OFFICE JAMES N.VANIJEGRIET, OF NEW YORK, N. Y., ASSIGNOR T INTERNATIONAL V BITUMENOILCORPORATION, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE FRAOTIONATINGTOWER AND SCRUBBER Application filed August 16, 1928. Serial No.299,927.

The object of my invention is to provide an apparatus for the fractionalcondensation of petroleum or hydrocarbon or other vapors from a still orretort into various by-prodi ucts such as paraffin, lubricating oils,gas

or fuel oils, gasoline, kerosene, naphthas, benzols and various otherproducts; and in the fullest embodiment of my invention there is alsoprovided means for scrubbing from the fixed gases any light condensiblevolatiles. All of these operations are adapted to be carried out in asingle tower consisting of a series of preferably superposed spiralcondensers similar in principle to the condenser disclosed in myco-pending application Serial No. 232360.

The simplicity of the present construction of condenser makes itpossible to provide a fractionating tower for condensing by-products, inwhich the tower will cost approximately one-fifth that of previousconstructions, and will'occupy but a fraction of the space occupied by Vfractionating towers formed of pipes or of dephlegmator bafileconstruction. By providing a plurality of separate units, each in itselfcomposing a condenser, various temperatures may be maintained in theseveral units by air circulation and by water cooling, so that differentfractions or condensates having specifically different characteristicsmay be withdrawn from the several units while the product is progressingsuccessively through the several units of the complete tower.

Other advantages will be set forth in the following detailed descriptionof my invention.

In the drawings forming part of this application,

Figure 1 shows an elevation with parts broken away, of a fractionatingtower composed of six different units in superposed relation, one ofwhich includes a scrubber,

Figure 2 is a plan view of the paraffin or heaviest oil condenser withthe cover removed, and V Figure 3 is a plan view of the unit which isemployed as a scrubber, showing it with the cover removed.

Figure 4 is a perspective view of the interior of the scrubber unit.

In the drawings I have shown a fractionating tower with the severalunits arranged in superposed relation and composed of six units A, B, C,D, E and F. In operation the oil or other vapors and fixed gases aredelivered from the petroleum refining still or retort, in the case of alow temperature carbonizationi plant, to the lower condenser A, and theyare, preferably, introduced at the center thereof through the pipe 11.These vapors and fixed gases travel through a spiral conduit 3. The unitA is shown composed of a receptacle consisting of a bottom wall 1 and acylindrical wall 2 having a removable cover 51 secured to the receptacleby bolts 6 with a packing ring 7 interposed between the cover and upperflange '5 of the receptacle. Preferably, the receptacle and its coverare insulated by a covering 4 of insulating material, so that only apartial reduction in temperature of the products will take place in theunit A, leaving the products still in a heated condition when they passinto the unit B as hereinafter described.

The spiral channel 3 through which the volatiles delivered from the pipe11 flow, is formed by a curved strip of metal 8 which starts near thecenter of the unit A and is coiled about itself in the form of a spiralhaving gradually increasing convolutions, so that this spiral stripgradually expands until its outer convolution approaches the cylindricalwall of the unit; and its outwardly turned end is preferably fastened tothis wall as shown at 52.

While the spiral strip 8 may have its convolutions separated from eachother in the manner shown in my said co-pending application I have shownin the present construction a spiral slot 53 formed in the under surfaceof the cover51 to receive one edge of the spiral strip 8, so that thegroove acts as a pocket for this edge of the strip 8 and holds theseveral convolutions in definite spaced relation. When the cover 51 isapplied to the flange 5 of the receptacle and clamped in place by thebolts 6, the strip 8 will rest in close contact with the bottom wall 1and will extend at the top into the spiral groove 53 so that the entireinterior of the unit A will be formed into a spiral channel into whichthe volatiles enter at the center, and thence travel a spiral co use incontact with the several convolut-ions of the strip 8, and with thecover and bottom wall of the unit. I prefer that this first unit beair-cooled; that is to say, the air circulating around the unit reducesthe temperature of the volatiles 1n the spiral channel 3 suiticiently toreduce the temperature of the volatiles for condensing the firstproduct. The volatiles passing through this spiral channel come intocontact with large radiating surfaces composed of the strip 8 and thebottom wall 1 and the cover 51, so that even though the products are inthis condenser a comparatively short period, they are reduced intemperature sufliciently to remove by condensation certain of theproducts. While I prefer to remove two different fractions of oil ofdifferent boiling points and densities in the unit A, the invention isnot limited to this method of operation. While the volatiles are passingthrough the spiral channel 3, some of them are precipitated bycondensation into a liquid accumulating in the bottom of the spiralchannel 3 and at 15 I have provided adam consisting of a metal wallbetween two of the convolutions of the strip 8 extending only partway ofthe height of the strip 8, so that the liquid precipitated on one sideof this dam may be drawn off through the outlet pipe 16.

In the treatment of petroleum products the material removed through thepipe 16 will generally be paratlin or heavy oil condensed from the hotvapors by cooling and while traveling up to the. point of the dam 15.

The pipe 16 forms part of a trap 55 which will entrap part of the fluidand prevent the escape of vapors through the pipe 56 which conducts theliquid away from the unit A. The vapors which pass beyond the dam 15 andtraverse the course of the spiral channel 3 will be subject to furthercondensing action and additional liquid will be precipitated before thevapors pass out of the discharge pipe 1 1. Such liquids as may becondensed beyond the dam 15 will be conveyed from the unit through thepipe 17 and the trap 57 and will be conducted away by the discharge pipeThe condensates removed through the pipes 16 and 17 will be differentfractions having different boiling points. If it is desired to removeonly a single fraction or con 'densate in the unit A the dam 15 may beomitted as well as the pipe 16 and in that case all of the condensate inthe unit A will be carried off through the pipe 17.

I have shown a covering or jacket 4 of refractory material covering onlythat portion of the cover 51 of the unit A up to the convolution of thestrip 8 where the dam 15 is located, leaving the portion of the coveroutside of and concentric therewith uncovered, and subject to thecooling effect of the air circulating over the cover. The effect ofleaving the. cover partially protected by the refractory material andthe other exposed to the circulating air will cause a more definitedemarcation between the fraction or condensate taken off through. thepipe 16 from that taken oil through the pipe 17.

I have provided a thermometer 18 projecting into the unit A and having areading portion extending out of the cover, and if the temperature atthis discharge end is below the desired low end point the insulatingmaterial 4 may be extended out to partially cover the unit A beyond thepoint of the dam 15 in order to regulate the condensation and to securethe discharge of the desired condensate through the pipe 17.

The vapors which are not condensed while passing through the unit Adischarge from this unit through the pipe 14 which latter conducts thevapors into the unit B which I have shown superposed directly over theunit A. The unit B is constructed similar to the unit A except that Ihave eliminated the insulating or refractory material. This unit has astrip 8 arranged in the form of a spiral, the same as in the unit A, andthe vapors admitted to the central point of the channel 3 circulatethrough this channel and these vapors are further cooled while passingthere through, so that part is precipitated in the form of a liquid. Thecondensate precipitated in the unit B will consist of lubricating oilsof lower boiling point than the condensate formed in the unit A. Thiscondensate is withdrawn from the unit 13 through the pipe and trap 59and is conveyed away. I have shown the unit B as air-cooled and a lowerboiling point condensate will be condensed in the unit B than thatformed in the unit A.

The products which still exist as volatiles after passing through theunit B are conducted through the pipe 60 and are fed into the center ofthe unit- 0 which is shown superposed above the unit B. In most respectsthe unit C is like the unit B and it has the same spiral channel 3formed by the strip 8 coiled about itself and dividing the space betweenthe shell and the cover to form this spiral channel. I

I have shown the unit C provided with a number of fins or flanges 61distributed across the bottom of the bottom wall Land a similar set offins or flanges 62 projecting from the cover 51. These flanges may becast integrallv with the cover and the bottom wall 1. The flanges orprojections, acting on the principle of convection serve to rapidlydissipate the heat from the product while traveling through the spiralchannel 3 in the unit C and by reason of the increased cooling actioneffected with these flanges the temperature of the products in thecondenser C may be brought down to the desired end point, so that gasoil or light lubricatingoil fractions may be condensed in the unit Cwhere the device is being used for petroleum products. The liquidprecipitated in the unit C is drawn out through the pipe and trap 63.

The unit D is shown superposed above the unit C and the unit E is shownsuperposed above the unit D, and as both of these'units are shown.similar in construction and operation they may be collectivelydescribed. Each of these units comprises a receptacle 8O correspondingwith the receptacles contained in the previously described units,together with a cover and gasket and having the spirally arranged metalstrip 8 between the bottom and the cover to divide the chamber into aspiral channel 3. The vapor chamber 80 in this case is submerged inwater to secure the desired cooling action. For this purpose I haveshown the chamber 80 arranged in a water tank 64, so that the chamberand its cover are submerged within the water contained within the tank.This water is perfectly circulated, the pipe 66 connected with the tankserving as an inlet for the water, and the pipe 67 arranged at theopposite point of the tank serves to carry off the water and therebymaintain circulation around the chamber 80. The parts thus described arethe same for the units D and E.

Instead of disposing the strips 8 in grooves in the cover member of theunits D and E I have shown channel pieces 9 bolted at intervals to thestrip 8, so that the flanges of these channel members serve to hold theadjacent convolutions of the strip 8 in the desired spaced relation.Ihave also shown members 10 attached at intervals to the strip 8 to actas baffles. Both the members 9 and 10 serve to deflect or bafiie thevapors passing through the spiral. channel 3 so that they are broughtinto contact with the bottom wall 1 and the cover 51 and with variousportions of the strip 8. The same members 9 and 10 correspond withsimilar members shown and described in my said co-pending application.The vapors are taken from the unit O through the pipe 68 and aredelivered to the center of the unit D so that these, vapors pass throughthe spiral channel 3 and while so traveling they are reduced intemperature to a point where the liquid formed by condensation of partof the vapors in the unit D will result in a fraction which willconsist, say, of kerosene. The condensate from the unit D is drawn oilthrough the pipe and vapor trap 70. The products still remaining in theform of vapors after passing through the condenser D are conducted bythe pipe 69 and are delivered to the central part of the unit E, so thatthe vapors pass through the spiral channel 3 in this unit and part ofthe vapors are condensed into liquid and are drawn oil through the pipeand trap 71. The

7 fraction thus removed from the unit E, where petroleum is the productunder treatment, will be, say, gasoline.

The fixed, non-condensible gases carrying with them a percentage oflight oil Vapors, pass out of the unit E through the pipe 72 and areconducted to the center of the scrubber F.

The scrubber comprises, in the embodiment shown hereof, an outer tank 73 through which water is circulated in the same man ner as in the'unitsD and E. The cooling water enters this tank through the pipe 66 and isdrawn off through the pipe 67 which, preferably, delivers the waterwhich has served for cooling in the. scrubber into the tank of the unitE, in order that in the latter the temperature of the water will beslightly raised by reason of the fact that it has previously served forcooling in the scrubber. In addition, the scrubber consists of a chambercorresponding with the unit A and it is provided with a cover and thestrip 8 coiled-in the form of a spiral is also present in this unit.Instead of the baffles or separators used in the other units, I haveshown here a number of blocks 74 which may be made of soft wood orasbestos, of sufficient strength to act as spacers to maintain theconvolutions of the strip 8 in spaced relation, and sufliciently porousto become'saturated with the heavy oil in the bottom of the scrubberchannel. This material must also be adapted to stand the heat andpreferably it withstands the heat applied at intervals to' drive off thelighter volatiles absorbed by the heavy scrubber oil placed in thebottom of the chamber. I have shown these blocks wide at the top toextend across the full width of the space between the convolutions ofthe strip 8 and below the blocks are cut away to form the narrowextensions 7 5 which project to the bottom of the shell 80. Theseblocks,

in addition to forming spacers for the convolutionsof the strip 8, actby capillary attraction to absorb the heavy, high boiling point oilwhich is admitted into the spiral channel 3 of the scrubber by means ofthe pipe 72 so that a layer of high boiling point oil is alwalys presentin the lower part of the channe 3. i

The high boiling point oil absorbs the light oil condensate from thefixed gases which are caused to travel through the long spiral chan- 1'nel 3 which are not only in contact with the oil at the bottom of thespiral channel but with the oil saturating the bafiie blocks 74. Thescrubbed gases may be withdrawn through the pipe 76 and may be stored ina gas holder (not shown). From time to time the scrubbingchamber may beremoved from its position in the water tank 7 3 and be subjected to heatfor the purpose of distilling oil the light volatiles absorbed by theoil and by the been necessary in the pipe forms of condensers, where thelatter were of return bend construction arranged in tanks, orconstructed of a series of nests of pipes and towers. In the presentdevice the vapors from the still up to the time they pass through thescrubber have a continuous travel in contact with large metalliccondensing surfaces and the units may be of uniform construction,compact, inexpensive and of efficient design. Each unit may be easilymaintained at the end point temperature for recovering the desiredby-product fraction. By employing a partial or complete refractorycovering for the first unit and by using air and water for circulationin subsequent units, the desired temperatures may be obtained forrecovering all of the desired fractions, each uniform in itself.

The present fractionating tower may occupy about one-fifth the space ofthe towers heretofore used and the cost of the same, as well as itsoperating and maintenance cost are much less than the previous forms oftowers.

Having described my invention, what I claim is:

1. In a device for condensation of vapors the combination of a shellforming a chamber, a cover for closing said chamber, one of said membershaving a spirally formed groove in one of its surfaces, and a striphaving one edge seated in said groove and disposed in spiralconvolutions and adapted to extend between said cover and the bottom ofsaid shell to form a spiral channel, and means for delivering vapors toand from said channel whereby they are caused to travel spirallytherethrough.

2. In a device for condensation of vapors, means forming a chamberhaving a strip disposed in convolutions and forming in said chamber aspiral channel, means for conducting vapors to and from said channelwhereby they are caused to travel spirally therethrough, a liquid tankin which said chamber is disposed and means for circulating liquid insaid tank for cooling the vapors traveling through said chamber, andmeans for withdrawing liquid condensate from said chamber.

3. In a scrubbing device for separating volatiles from non-condensiblegases the combination of means forming a chamber, a strip disposedtherein in convolutions and forming a spiral channel through which thevapors are adapted to be conducted, means for conducting vapors to andfrom said channel whereby they are caused to travel spiral lytherethrough, and blocks of absorbent material disposed in said channelfor absorbing condensible volatiles from non-condensible gases.

4-. In a scrubber for separating volatiles from non-condensible gases,means forming a chamber, a strip disposed therein in convolutions andforming a spiral channel in said chamber, means for conducting vapors toand from said channel whereby they are caused to travel spirallytherethrough and blocks of absorbent material disposed in said channeland having passages thereth rough for the circulation of vapors.

5. In a scrubber for separating condensible volatiles from fixed gases,means forming a chamber, a strip disposed therein in convolutions toform a spiral channel, means for conducting vapors to and from saidchannel whereby they are caused to travel spirally therethrough, meansfor supplying a layer of absorbent liquid in the lower portion of saidchamber and blocks of absorbent material disposed in said channel andextending substantially across the upper portion of said channel andhaving narrower portions projecting into the liquid in the lower portionof said chamber.

6. In a device of the character described the combination of pluralityof separate units in which vapors are adapted to be cooled, each unitcomprising a chamber having a spirally formed channel, a scrubbercomprising a chamber having a strip therein disposed in convolutions toform a spiral channel, absorbent material in said channel for collectingcondensible volatiles by absorption, and means for conducting vaporssuccessively through the spiral channels of said condensing units andsaid scrubbing unit.

7. A device for the condensation of vapors into liquid, comprising meansforming a chamber, a strip disposed between the bottom and top of thechamber, and spiral convolutions to form a spiral channel, means forconducting vapors to and from said channel whereby they are caused totravel spirally therethrough, a dam in said channel extending partway ofthe height thereof whereby liquids may be condensed on either side ofsaid dam and vapors may pass over the dam, and separate means forwithdrawing liquid condensed on different sides of said dam.

8. In a device for the fractional condensation of vapors the combinationof a plurality of separate units, each unit having a spiral channel forthe travel of fluid, one of said units comprising a chamber having acovering of heat insulating material, and another comprising a chamberwithout insulating covering whereby it will be subjected to the directcooling action of the surrounding air, means for causing vapors totravel through the channels of said units in series, and means forwithdrawing the condensates separately from said units.

9. In a device for the fractional condensation of vapors the combinationof a plurality of separate units, each having a spiral channel for thetravel of fluid, one of said units comprising a chamber exposed to thecooling action of the surrounding air, another of said units comprisinga chamber, a liquid tank in which said chamber is disposed, means forcirculating liquid in said tank for cooling the vapors traveling throughsaid second chamber, means for causing vapors to travel through saidchambers in series, and means for withdrawing the condensates separatelyfrom said units.

10. In a device for fractional condensation of vapors, the combinationof a plurality of separate units, each unit having a spiral channel forthe travel of fluid, means for causing vapors to travel through theseveral units in series, and means for withdrawing the condensatesseparately from the several units, one of said units comprising achamber, having a covering of heat insulating material to retard theradiation of heat from said unit, another unit comprising a chamberwithout insulation whereby said chamber will be subject to the directcooling action of the surrounding air, and a third unit comprising achamber, a liquid tank in which said chamber is disposed, and means forcirculating liquid in said tank for cooling the vapors in the chamber ofsaid third unit.

Signed at the city, county and State of New York, this 26th day of May,1928.

JAMES N. VANDEGRIFT.

